Anything in the plots below approx 410 NM is extrapolated from the numbers above that value on the spectrometers that do not expose with UV light or do not measure into UV light. The plot of the iSis set to Normal? should have been based on the measured UV absorption by the OBAs, so closer to reality. The Lab numbers tell something about the 380-700 NM range and will contain some guesswork for the range below approx 410 NM.

With the ColorMunki the measurement is not going further than 430 NM and the output numbers below that value are copied from the 430 NM measurement. Based on your plots I now tend to think that the UV-"Cut" iSis is not measuring below 430 NM either where I first though it might go down to 400 NM.

I've seen your plots too, I like to experiment myself.My UV Fluorescence 380nm - 730nm measurements proove the oposite, perhaps my instrument is different I have original Gretag-Macbeth not X-rite.

The i1Pro sucessfuly reads from 380 to 730, on non fluorescent sample there is flat line graph, no erroneous data.The samples are measured using special adapter, precission power supply, UV light source etc.Data is constant and repeatable.

I've seen your plots too, I like to experiment myself.My UV Fluorescence 380nm - 730nm measurements proove the oposite, perhaps my instrument is different I have original Gretag-Macbeth not X-rite.

The i1Pro sucessfuly reads from 380 to 730, on non fluorescent sample there is flat line graph, no erroneous data.The samples are measured using special adapter, precission power supply, UV light source etc.Data is constant and repeatable.

The right attitude. However if you send a message here it might help others if you specify the paper measured, the surface your target is measured on.

To what do you get opposite results? To what I wrote in my message here or to the paper white spectral plots I publish?

I got the impression from your first message that you measured with two spectrometers: a UV-Cut Eye 1 Pro and an iSis, the last used for a UV-Cut and a UV enabled measurement. I tried to explain that for both UV-Cut measurements the plot below 400Nm or 430 NM is a software extrapolation based on the measurement above that value, more guesswork than measured data.

Your second message seems to imply that you use a normal Eye 1 Pro so one that measures into UV. Or you assume that the file with measurements from your UV-Cut spectrometer that shows reflection data from 380 to 730 NM is enough evidence that the meter measures below 400 NM. That is not correct, see Robin Myers comments in the link above. If it did measure below 400 NM it would not be a UV-Cut instrument. Could you make it clear which instrument you used?

Where you mention a special adapter, precision power supply, UV light source etc I guess you refer to the iSis. I am not aware of that kind of parts for the Eye 1 Pro.

It would not surprise me if a spectral plot of an iSis in UV mode differed below say 420 NM to a spectral plot of a normal Eye 1 Pro that also measures into UV. The light source of the iSis is a UV LED as I understand it and the Eye 1 Pro is using a tungsten light source. Differences in the UV spectral output of the lamps will trigger (different) OBAs differently. So did my Spectrocam with a Xenon flash. The standards for spectrometers have not been that tight. Manufacturers like Gretag Macbeth and X-Rite will massage the measurements that they are not conflicting too much and deliver usable data to create profiles that can work. 1000-5000 $ instruments are a blend of science, manufacturer and user experience plus compromises that give practical results for 90% of the cases where a 100K $ instrument may deliver 99% practical results.

The eye-one pro uv cut and non uv-cut can both measure UV data. The problem is almost nobody taken their eye-one apart and do not know that both devices filter the light source not the light that reach the sensor.

So both devices can measure UV in emmision mode.

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I got the impression from your first message that you measured with two spectrometers: a UV-Cut Eye 1 Pro and an iSis, the last used for a UV-Cut and a UV enabled measurement. I tried to explain that for both UV-Cut measurements the plot below 400Nm or 430 NM is a software extrapolation based on the measurement above that value, more guesswork than measured data.

Yes I used eye-one uv cut, isis and special device to make eye one measure uv in emission mode.

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Your second message seems to imply that you use a normal Eye 1 Pro so one that measures into UV. Or you assume that the file with measurements from your UV-Cut spectrometer that shows reflection data from 380 to 730 NM is enough evidence that the meter measures below 400 NM. That is not correct, see Robin Myers comments in the link above. If it did measure below 400 NM it would not be a UV-Cut instrument. Could you make it clear which instrument you used?

See above.

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Where you mention a special adapter, precision power supply, UV light source etc I guess you refer to the iSis. I am not aware of that kind of parts for the Eye 1 Pro.

The special hardware was made by me because mesurements must be made in emission mode, I did not refer to any hardware made by x-rite.

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It would not surprise me if a spectral plot of an iSis in UV mode differed below say 420 NM to a spectral plot of a normal Eye 1 Pro that also measures into UV.

That is topic of this thread, I ask for anyone who has i1Pro2 and isis to measure same paper in both modes and then post spectrum data here in this thread.

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The light source of the iSis is a UV LED as I understand it and the Eye 1 Pro is using a tungsten light source. Differences in the UV spectral output of the lamps will trigger (different) OBAs differently. So did my Spectrocam with a Xenon flash. The standards for spectrometers have not been that tight. Manufacturers like Gretag Macbeth and X-Rite will massage the measurements that they are not conflicting too much and deliver usable data to create profiles that can work. 1000-5000 $ instruments are a blend of science, manufacturer and user experience plus compromises that give practical results for 90% of the cases where a 100K $ instrument may deliver 99% practical results.

Yes I understand this but what is strange that the height of the graph is dofferent almost as it would show that same surface reflecting less light for isis than i1pro. Can't X-rite calibrate both devices to measure at least this the same?I'm not talking about graph differences like here and there, but spectral power should be calibrated.

The surface is 5 sheets of same paper to prevent color from changing. Paper is kodak Rapid-dry.

The eye-one pro uv cut and non uv-cut can both measure UV data. The problem is almost nobody taken their eye-one apart and do not know that both devices filter the light source not the light that reach the sensor.

So both devices can measure UV in emmision mode.

Yes I used eye-one uv cut, isis and special device to make eye one measure uv in emission mode.

See above.

The special hardware was made by me because mesurements must be made in emission mode, I did not refer to any hardware made by x-rite.

That is topic of this thread, I ask for anyone who has i1Pro2 and isis to measure same paper in both modes and then post spectrum data here in this thread.

Yes I understand this but what is strange that the height of the graph is dofferent almost as it would show that same surface reflecting less light for isis than i1pro. Can't X-rite calibrate both devices to measure at least this the same?I'm not talking about graph differences like here and there, but spectral power should be calibrated.

X-Rite calibrates the spectrometers as integrated instruments, I do not think that you should expect the bare sensors to act equally on DIY light sources of whatever optical geometry. How long ago were both instruments actually serviced by X-Rite?

Removing the filter in the Eye 1 Pro does two things if Robin Myers is right: it takes away the yellow UV filter on the light source (outer circle) and a blue filter in the centre that affects the sensor.

I think in general you have too many loose ends in your experiment to draw any conclusion from the results and it could have been a more serious and shorter thread if you had given all the details right from the start.

X-Rite calibrates the spectrometers as integrated instruments, I do not think that you should expect the bare sensors to act equally on DIY light sources of whatever optical geometry. How long ago were both instruments actually serviced by X-Rite?

All spectrums except UV are from instruments without any modifications, they are recertified every year as recommended by manufacturer.

Removing the filter in the Eye 1 Pro does two things if Robin Myers is right: it takes away the yellow UV filter on the light source (outer circle) and a blue filter in the centre that affects the sensor.

Most judge the negative Lab b as an indication of OBA content. However a blue colorant or suppression of the warm end of the spectral reflectance could create that effect too, you will see a drop of the L though. The graphic industry takes the reflectance at 457 NM and calls it brightness, which usually means that the reflectance over a wider range can be neglected by the manufacturer so OBA addition becomes the cheap answer to get that number high.

I am interested in the entire white reflectance and spectral plots tell more then. The Eye 1 Pro does not have the best light source to create fluorescence but enough to see the OBA effect. 350 papers measured consistently with 3 measurements each makes it worthwhile; enough to tell what papers might create "metamerism" due to the paper OBAs, what papers may prove to be paper white shift prone in time, which papers are identical, which papers have the best reflectance over the entire spectral range, front and back differences, opaqueness, etc. There are better industry tests for each aspect but the total number of consistent measurements and the presentation of the spectral plots works for me and for more people.

Old thread but perhaps somebody can post the paper white spectral data from i1Pro2 and i1Pro for UVcut and no UV filter ?I understand that it's rare that you have both i1Pro with filter and without, but I would liketo see comparison to i1Pro2.

Are your papers measured always with the same instrument, is it the new i1pro2 now? I have some data and would like buy new i1pro2 but I do not like the idea that it will measure differently. And the spectrum plots will not be comparable with older data.